Field of the Invention
The present invention relates in general to the field of information handling system touch input management, and more particularly to an information handling system low latency touch rejection buffer.
Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Portable information handling systems often accept end user inputs as touches made to a touchscreen liquid crystal display (LCD). For example, tablet information handling systems are built into a planar housing that does not include a physical keyboard. In order to interact with such a tablet information handling system, the user typically activates a keyboard for presentation at the LCD and types inputs at the presented keyboard that are detected by a capacitive touch surface of the LCD. Eliminating a physical keyboard reduces the housing size, thus providing convenience and portability for the end user.
Including a touchscreen in a tablet information handling system also provides the end user with other types of touch inputs that tend to be more intuitive than keyboard inputs. For example, the end user touches the screen to make a mouse input, thus allowing the end user to make convenient cursor movements and drop, drag and copy operations. In some instances, end users may handwrite inputs on a touchscreen instead of using a keyboard. Logic running on the portable information handling system analyzes touch movements to determine letters traced by the end user's finger. More precise writing inputs may be performed with a stylus that includes a capacitive device sensed by the capacitive touch surface. In addition to supporting handwritten letters, tablet information handling systems may also support drawings done on the capacitive touch surface both by a finger or a stylus.
One difficulty with using touchscreens to accept finger and/or stylus inputs is that end users will often touch the display without an intention to make an input. Generally, keyboard controllers on information handling systems that include touchscreens apply one or more input detection algorithms to distinguish between intended and unintended touches. An example of such an input detection algorithm is a “large object” detection algorithm designed to reject touch events that encompass an area of greater than a defined size, such as 25 mm. Such input detection algorithms tend to have low latency requirements so that end users do not experience excessive delays between the timing of an input and the presentation of the input at the display. The low latency often means that initial small areas of touch that precede a larger touch area may be detected as an intended touch and presented as such to the end user. For example, an unintended dot or line is written before the large object detection algorithm engages to reject further touch events. Typically, when writing with a finger a user will not rest his palm on a touchscreen; however, when writing with a stylus a user often will rest his palm on the touchscreen to produce an unintended dot or line.